Heat exchanger suitable for vehicles

ABSTRACT

A heat exchanger, in particular a brazed heat exchanger ( 1 ) for motor vehicles, has at least one header tank ( 2 ) having two junction pieces ( 3, 4 ), a binocular-shaped flange ( 7 ) for the fastening of pipes and being inserted into the junction pieces ( 3, 4 ) which are arranged adjacently at a spacing a with respect to one another. The flange ( 7 ) can be produced from plastic and is formed in two parts, so that it is divided essentially in a plane T which is arranged between, preferably at half the spacing “a” between, the junction pieces ( 3, 4 ).

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

The right of foreign priority is claimed under 35 U.S.C. § 119(a) basedon Federal Republic of Germany Application No. 10 2004 028 655.8, filedJun. 15, 2004, the entire contents of which, including thespecification, drawings, claims and abstract, are incorporated herein byreference.

BACKGROUND OF THE INVENTION

The invention relates to a heat exchanger, in particular a brazed heatexchanger suitable for use in motor vehicles, and to a pipe junctionelement for such heat exchangers.

Heat exchangers, in particular radiators or heaters for motor vehicles,have flowing through them on the primary side a fluid, in particular themotor vehicle engine coolant. Connection to the coolant circuit takesplace via junction or connection pieces on the heat exchanger which areconnected to pipe junction lines for the coolant. Various pipe junctionconnections are known, depending on the type of construction of the heatexchanger or of its header tank, on which the junction pieces arelocated. The commonly assigned DE-A 35 17 488 discloses a heat exchangerwith a plastic water tank having junction pieces injection molded ontothe tank. Coolant junction pipes are inserted into these junction piecesand are secured via a securing clip, which may be referred to as aninsertion fork. Similar pipe junction connections are known fromcommonly assigned DE-C 197 37 704. Where brazed heat exchangers areconcerned, both the water tank and the junction pieces which are brazedinto the water tank also consist of metal, preferably of aluminum. Theinsertion fork connection known for plastic junction pieces istransferred in modified form to metallic junction pieces, as proposed inDE-A 44 03 402, DE-C 196 21 282 or DE-A 197 40 115 or DE-A 197 52 139.

Another form of a pipe junction is known from commonly assigned DE-A 19648 162, specifically for a brazed heat exchanger with junction piecesbrazed into the water tank. The coolant junction pipes are inserted intothe junction pieces and sealed off by means of O-rings, axial fixing ofthe junction pipe in the junction piece located on the heat exchangerside taking place by means of what may be referred to as a holding clipring which engages over an annular bead on the junction pipe and anannular flange on the junction piece. This type of insertion connectionpermits rapid mounting, that is to say a rapid junction of the coolanttubes to the heat exchanger in the vehicle. In order further to simplifymounting, it is also known to connect the coolant junction pipes to theheat exchanger via a flange, in which the inflow pipe and return pipeare combined. In this case, the heat exchanger has provided on it afirst flange which is connected to a second flange in the vehicle inorder to produce the coolant junction. For brazed heat exchangers, it isknown to produce the flange as an aluminum part which is brazed to theheat exchanger. This brazing or soldering is relatively costly.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a heat exchanger or apipe junction element of the type initially mentioned more simply andmore cost-effectively in terms of its pipe junction connection.

According to one aspect of the invention, there is provided a heatexchanger suitable for motor vehicles, comprising: at least one headertank having two junction pieces arranged at a predetermined distancefrom one another, for connecting coolant pipes; and a binocular-shapedflange for fastening pipes to the junction pieces and being insertedinto the junction pieces, wherein the flange comprises a plasticmaterial and is formed in two parts, divided essentially along a plane Twhich is arranged between the junction pieces.

According to another aspect of the invention, there is provided a pipejunction element, comprising: a binocular-shaped flange for fastening ofpipes to corresponding fixed connection pieces that are located apredetermined distance from one another, wherein the flange is comprisedof a plastic material and is formed in two parts, divided essentiallyalong a plane T which is arranged between the junction pieces.

Further objects, features and advantages of the present invention willbecome apparent from the detailed description of preferred embodimentsthat follows, when considered together with the accompanying figures ofdrawing.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing:

FIG. 1 is a perspective view showing a detail of a heat exchanger withjunction pieces and a heat exchanger flange, and

FIG. 2 is a perspective view showing a modified heat exchanger withjunction pieces and a heat exchanger flange.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the invention, the flange is produced from plastic and isformed in two parts. By the chosen material being plastic, the flangecan be produced at lower cost. The plastic flange is produced in theform of two injection moldings which are inserted into the metallicjunction pieces of the heat exchanger which is preferably designed as aheat exchanger for a motor vehicle. Since the brazed heat exchanger,together with its junction pieces, consists of metal, preferably ofaluminum, there would be tolerance problems regarding the junction piecespacing in the case of a one-piece flange consisting, for example, ofplastic or else of aluminum or of an aluminum alloy. This problem issolved by dividing the flange into two flange halves having anadjustable spacing. Owing to the two-piece character or the division,the flange can be adapted with its connection pieces to thepredetermined spacing of the heat exchanger junction pieces. Thisresults in lower production costs for the heat exchanger, including theheat exchanger flange, the function remaining the same, as compared withthe prior art. The vehicle-side counterflange, which is connected to theheat exchanger flange for fastening the coolant junction pipes, cantherefore also be produced from plastic, aluminum or an aluminum alloy,thus leading to a further cost reduction in the heating circuit.

FIG. 1 shows a detail of a heat exchanger 1 with a header tank 2, alsocalled a water tank. The heat exchanger 1 is designed as a brazedall-aluminum heat exchanger and is used for the heating of air for avehicle interior, not illustrated, of a motor vehicle. The water tank 2has two junction pieces 3, 4 which likewise consist of aluminum and arebrazed into corresponding rim holes 2 a, 2 b on the water tank 2. Apartition, not illustrated, is located between the two junction pieces3, 4 in the water tank 2 and has the effect of a U-shaped flow throughthe heat exchanger 1, not illustrated in full (deflection of the coolant“in width”). One of the two junction pieces 3, 4 is therefore the inflowjunction piece and the other the return junction piece. The two junctionpieces 3, 4 each have an annular flange, not fully viewable here, overwhich engages in each case a holding clip 5, 6 which is designed as anopen ring and is known per se, for example, in a similar form, from theinitially mentioned commonly owned DE-A 196 48 162. The two junctionpieces 3, 4 have a fixed spacing “a” (from junction piece longitudinalaxis to junction piece longitudinal axis). This heat exchanger thus faris of conventional design.

According to the invention, the heat exchanger 1 has connected to it aflange 7 (double flange) made from plastic, which has a spectacle-shapedor binocular-shaped design and consists of two identically designedflange halves 8, 9, the flange half 9 being illustrated onlyincompletely (by broken lines). The following description of the flangehalf 8 therefore also applies accordingly to the flange half 9. Eachflange half 8, 9 has a passage bore 8 a, 9 a which has a spacing “a′”corresponding to the spacing “a”, that is to say the passage bores 8 a,9 a are in alignment with the junction pieces 3, 4. The flange half 8has, on the side facing the water tank 2, a connection piece 8 b whichis inserted in a way not fully viewable into the junction piece 3 of theheat exchanger 1, is sealed off by sealing means, not fully viewable,and is fixed axially by the holding clip 5. For this purpose, there isarranged on the end face of the connection piece 8 b an annular flange 8c (only partially visible), over which parts of the holding clip 5engage. The flange 7 is thereby connected with its two flange halves 8,9 to the heat exchanger 1 mechanically and in a fluid-tight, that is tosay coolant-tight, manner.

The flange 7 is divided in a dividing plane T which is indicated by abroken line and which runs along a line bisecting the spacing distance“a”. The flange half 8 has in its circumferential region a tab 8 d inthe vicinity of the dividing plane T, while the opposite flange half 9has, in its corresponding circumferential region, a latching hook 9 ewhich engages into the tab 8 d and is latched together with the latter.A corresponding latching connection is provided on the oppositenonvisible side of the two flange halves 8, 9, the tab being provided onthe flange half 9 and the latching hook being provided on the flangehalf 8, that is to say exactly in reverse to the above. The two flangehalves 8, 9 are held together by means of this two-sided latchingconnection. A sheet metal nut 10 is introduced between the two flangehalves 8, 9 in the region of the dividing plane T and serves as anabutment for a screw connection to a counterflange, not illustrated.This counterflange receives the ends of coolant junction pipes, notillustrated, and connects these to the heat exchanger-side flange 7.Simple and rapid mounting, that is to say rapid coolant junction, isconsequently possible.

As mentioned, the two flange halves 8, 9 are designed as what may bereferred to as identical parts and can therefore be produced by means ofthe same injection molding die. The plastic used is preferably PPA, PAor another plastic.

The heat exchanger flange 7 is mounted by the connection piece 8 b, andthe second connection piece, not illustrated, is inserted into the heatexchanger-side junction pieces 3, 4, with subsequent axial interlockingby means of the holding clips 5, 6. During this mounting operation, thespacing a′ of the two flange halves 8, 9 or of their passage bores 8 a,9 a is still somewhat variable, that is to say can be adapted to thespacing a of the heat exchanger-side junction pieces 3, 4. The twolatching connections are therefore not yet closed, this taking placeonly when both connection pieces of the flange halves 8, 9 are receivedcentrically or coaxially by the heat exchanger-side junction pieces.Owing to this variability of the spacing “a′” of the flange 7, toleranceproblems between the plastic flange 7 and the aluminum heat exchanger 1can be ruled out. If the plastic flange 7 were in one piece, that is tosay undivided, it would be necessary to reckon on manufacture-relatedand material-related deviations for the dimensions “a” on the heatexchanger side and “a′” on the flange side, and, if there were nocompensating possibility, these deviations would lead to tilting,jamming, stresses and/or leaks. These problems are eliminated by theflange being divided according to the invention.

FIG. 2 shows a modified exemplary embodiment of the invention with aheat exchanger 11 consisting of a tube block 12 and of two water tanks13, 14. In a modification of the previous exemplary embodiment, thisheat exchanger 11 has a longitudinal partition 15 in the water tank 14,junction pieces 16, 17 being located on both sides of the longitudinalpartition 15. The coolant flowing through the heat exchanger 1 is thusdeflected “in depth” or back-to-front, that is to say in or opposite tothe flow direction of the air flowing through the block 12. The junctionpieces 16, 17 are therefore arranged “obliquely” with respect to oneanother. In this arrangement, too, a two-part flange 18 made fromplastic, for the fastening of coolant junction pipes is provided, whichis designed basically identically to the flange 7 according to FIG. 1.The flange, preferably produced from PPA, consists of two flange halves19, 20 which are likewise held together by means of a latchingconnection, not described in any more detail here, but of similardesign. So that the two flange halves 19, 20 can be joined moreeffectively, centering means are provided in the region of the dividingplane: the flange half 19 or 20 therefore has a locating pin 19 ainjection-molded on and a locating bore 19 b, with a locating pin and alocating bore (not illustrated) likewise being provided, offsetlaterally, on the other flange half 20 (broken lines). The centeringmeans make it easier to mount the two flange halves and make it possibleto adapt the spacings “a”, “a′” described in relation to the exemplaryembodiment according to FIG. 1. A sheet metal nut 21 for screwing to thecounterflange, not illustrated, is also introduced into the flange 18.

The foregoing description of preferred embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and modifications and variations are possible and/or would beapparent in light of the above teachings or may be acquired frompractice of the invention. The embodiments were chosen and described inorder to explain the principles of the invention and its practicalapplication to enable one skilled in the art to utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the scope of theinvention be defined the claims appended hereto and that the claimsencompass the disclosed embodiments and their equivalents.

1. A heat exchanger suitable for motor vehicles, comprising: at leastone header tank having two junction pieces arranged at a predetermineddistance from one another, wherein the junction pieces are configured tobe connected to coolant pipes; and a binocular-shaped flange configuredto fasten pipes to the junction pieces, wherein the flange is insertedinto the junction pieces, wherein the flange comprises a plasticmaterial and is formed in two parts, divided essentially along a planearranged between the junction pieces; wherein the flange comprises twoidentically shaped flange halves capable of being latched with oneanother; wherein the flange halves comprise connection pieces which canbe received by the junction pieces; wherein the connection pieces arefixed in an axial direction by holding elements comprising elasticallydeformable clip elements.
 2. The heat exchanger as claimed in claim 1,wherein the flange halves can be produced as identical injectionmoldings from a single die.
 3. The heat exchanger as claimed in claim 1,wherein the flange comprises polyphthalamide.
 4. The heat exchanger asclaimed in claim 1, wherein each flange half has a tab circumferentiallyprojecting beyond the dividing plane, and on a diametrically oppositecircumferential side a latching hook, and wherein the two flange halvescan be latched together via the tab and the latching hook.
 5. The heatexchanger as claimed in claim 4, wherein the connection pieces have aspacing with respect to one another which corresponds to thepredetermined distance of the junction pieces, wherein the distance ofthe connection pieces can be fixed by latching the tab and latchinghook.